It is a time consuming process to construct in 2D or in 3D space a graphical representation of an object which includes elliptical segments. Elliptical segments are segments bounded by linear radial elements and elliptical tangential elements. Linear radial elements are rectilinear elements that extend out from a common origin like spokes in a wheel. Elliptical tangential elements are curved elements whose curvature follows an elliptical path like a frame of an elliptical mirror. Elliptical segments may be part of complex elliptical designs for example used in architecture for door windows, windows or other applications.
At present, to generate an image incorporating elliptical segments requires that the segments be calculated and then drawn either on paper or on a computer. However, the image so created is specific to the attributes which are given (length, width, number of elements and the like), and cannot be used except with such attributes. Changing any value of the attributes of the segments such as number or width of linear radial elements, number, width or ellipticity of elliptical tangential elements usually requires redrawing the entire image of the elliptical segments.
To alleviate this problem computer graphics systems sometimes include a database with geometric data for a finite number of pre-constructed instances of objects with elliptical segments. The usability of such graphics systems remains limited to the selection of those instances which are stored in the database. Changing the total width or length of such a pre-constructed object typically will result in anamorphism which the user cannot correct. Such anamorphism, in the context of a computer graphics system for design, such as an architectural modelling program, is clearly unacceptable, because of the loss of dimensional accuracy and the geometric distortion which results.